LONDON -- Heathrow Airport introduced a new security system for some of its passengers Friday, requiring them to undergo iris scans and be fingerprinted before boarding their flights.

The biometric data will be taken at Heathrow's Terminal 1, which has separate domestic and international lounges.

The information is only required for domestic passengers at the terminal who want to visit the larger international lounge before boarding their flights, or passengers who arrive on an international flight and transfer to a domestic one, said a spokeswoman for Heathrow Airport owner BAA PLC.

In addition to the photo ID and boarding pass that all passengers must produce at their boarding gate, these customers also will be identified with the iris scan and fingerprint, the spokeswoman said, speaking on condition of anonymity in keeping with BAA's regulations. The biometric data are destroyed within 24 hours, she said.

Domestic passengers who do not want to visit the international lounge at Terminal 1 are not required to provide such data, the spokeswoman said.

She said the test program is designed to improve security at the airport.